Evaluation of nutritional quality in spiralling whitefly (Aleurodicus dispersus Russell) infested mulberry (Morus sp.) foliage

摘要

The quality of mulberry ( Morus spp.) leaves play a vital role in the nutritive requirement of silkworm ( Bombyx mori L.) a monophagous insect domesticated for the production of natural fiber, silk. The mineral elements comprise major part of nutritional quality of mulberry leaves, which may alter due to injury caused by pests and diseases. Spiralling whiteflies are small insect pest feeds on mulberry leaves by sucking sap from the phloem through a slender stylet. This sap sucking nature of the pest may alter the mineral nutrients level in the leaves. Hence, an effort has been made to know the variations in the mineral nutrition of mulberry foliage under infestation. Six macro (nitrogen, phosphorus, potassium, calcium, magnesium and sulphur) and seven micro nutrients (zinc, iron, manganese, copper, boron, molybdenum and chloride) were analyzed in six popular indigenous mulberry varieties (M5, MR2, Mysore local, S36, S54 and V1). All the nutrients were decreased in the pest infested leaves of almost all the varieties; except three nutrients magnesium in M5 and S36; sulphur in Mysore local; zinc in S54 varieties increased. However, no changes were observed in the contents of nitrogen M5, MR2, Mysore local and V1; phosphorus Mysore local; potassium in M5 and V1; calcium MR2 and V1; sulphur in S54; zinc in M5 and V1; iron in M5; manganese in MR2; copper in M5; boron in S36; molybdenum in M5, MR2, Mysore local and S54 and chloride in M5, MR2 and S36 varieties. Variations in these mineral elements resulted in the nutritionally inferior mulberry leaves production. Feeding such leaves will affect the growth and development of silkworms which in turn adversely brings down the quality of silk production.